Echo satellite during inflation tests, 1960.
© National Aeronautics & Space Administration / Science & Society
Echo 1, a spherical balloon with a metalized skin, was launched by NASA on 12th August 1960. Once in orbit the balloon was inflated until it reached its intended diameter of 30 metres and it was then used as a reflector to bounce radio signals acros the oceans. Echo was simply a radio mirror in the sky, and its efficiency decreased as the gas which inflated the balloon gradually escaped and it lost its shape.